I am trying to print all Pythagorean triplets in haskell and while the logic is correct, i get error in parsing in line: funcp :: Int Int Int -> IO () . Can someone help me find the issue? I am very new to haskell

checkp :: Int->Int-> IO()
    checkp nn m= do
        let n=1
            if n<m
                then funcp m n nn 
                else checkp nn (m 1)
    funcp :: Int Int Int -> IO ()  


             
    
    
                

CodePudding user response：

You have wrong indentation:

checkp :: Int->Int-> IO()
    checkp nn m= do
        let n=1

here:

  --        *
            if n<m
                then funcp m n nn 
                else checkp nn (m 1)

while your error probably points you to the following statement after that:

    funcp :: Int Int Int -> IO () 
    ....

Syntactically, this if must start at the same column as the preceding line, namely here, let.

For more, check out the "do notation".

Of course the following is also an indentation error, at the very start of your code:

checkp :: Int->Int-> IO()
    checkp nn m= do
--  ^^^

They too must start at the same indentation level.